Controlling-brake for motors.



No. 660,054. Patented Oct. 16, I900.

A. C. EASTWOOD.

CONTROLLING BRAKE FOB MOTORS.

(Application filed May 14, 1900.) (N0 MfldeL) 2 SheetsESheet l.

fiz 54 M WW Patented Oct. l6, I900. 000.

FOR MOTORS.

ad m 14, 1900.

2 S heets$heet 2.

A. c. 'EASTW CONTROLLING BRAKE (Application in (No Model.)

UNITED STATES PATENT OFFICE.

ARTHUR O. EASTlVOOD, OF ENSLEY, ALABAMA, ASSIGNOR TO THE ELEU'TtICCONTROLLER AND SUPPLY COMPANY, OF CLEVELAND, OHIO.

CONTROLLING-BRAKE FOR MOTORS.

SPECIFICATION forming part of Letters Patent No. 660,054, dated October16, 1900.

Application filed May 14,1900. serial No. 16,635. (No model.)

To all whom it may concern:

Be it known that I, ARTHUR C. EAsTWooD, a citizen of the United States,and a resident of Ensley, Alabama, have invented certain Improvements inControlling-Brakes for Motors, of which the following is aspecification.

My invention relates to certain improvements in controllers for electricmotors.

I have shown my invention applied to the controller for which a patentwas granted to A. O. Dinkey on July 7, 1896, No. 563,575.

The object of the invention is to apply a braking force to a motor bymeans of connections on a controller which will make the motor act as agenerator, the speed being controlled by varying the resistance incircuit.

Referring to the accompanying drawings,

Figure l is a perspective view of my improved 2o cont-roller. Fig. 2 isa diagram View showing the wiring when my invention is used inconnection with a Din key controller. Fig. 3 is a diagram view of amodification. Fig. 4 is a view showing diagrammatically the circuitsthrough the controller and motor when the controller-handle is so thrownas to change the motor to a generator.

H is the frame of the controller, having a cylindrical slate tablet H,to which the contact-plates are secured.

I is the contact-arm, mounted on the shaft 1, having its hearings in theframe, and this shaft is geared to an operating-lever J in a mannersimilar to that described in the Dlnkey patent, above referred to. Thereare two series of concentric contact plates or blocks, one mountedwithin the other, and on the arm are contactfingers f t', which makecontact with the plates or blocks.

40 B, B B and B of the outer circle B and B pf the inner circle are thements which are required by the brake. necessary connections betweenthese ments are made by the fingers of the con- 5 troller-arm. No changein or addition to these fingers is made necessary by the addition of myimproved brake mechanism to the controller.

The blocks R to R inclusive, represent the resistance-blocks found onthe Dinkey type of controller, while the blocks D D D and seg- The seg-D of the outer series and the blocks D D D D of the inner series aredead-blocksthat is, when the fingers of the controller-arm are on theseblocks the motor is receiving no current and can coast under its ownmomentu m. The plates 0 O are contact-plates, upon which the fingers ofthe contact-arm rest when covering any pair of the resistanceblocks. If,for instance, the controller-arm is in the extreme position a I) when itis desired to stop, resistance is cut in through the resistance-segmentsR R &c. When the segments D, D D and D are reached by the fingers of thecontact-arm, the motor receives no current, as mentioned above, andcoasts under its own momentum. As it moves into the next position B isconnected to B and B to B, as shown diagrammatically in Fig. 4. Thisconnects the motor as a series generator, the connections beingsuch thatthe currentgenerated tends to build up the residual magnetism of thefields. This throws a load'on the ar mature, and it comes to restimmediately or gradually as it is allowed to generate moreorlesscurrent. Followingthecontroller-arm from the other extremeposition 0 d to the horizontal position, it will be seen that B is nowconnected to B and B to B. This reverses the connections of the armatureand fields; but since the armature is traveling in the oppositedirection the electromotive force is also reversed, and hence thecurrent traverses the field-coils in the same direction as before andthe machine builds up as a generator.

For regulating the current generated, and hence the braking force, inthe case of the trolley or hoist of a crane, where the momentum of theload is never Very great, in place of connecting B to a it may beconnected to any of the resistance-segments R R the. ,thus throwing moreor less resistance in the circuit.

I have found by experiment that the current generated in the above casesis so small 5 and of such short duration that the controller resistanceis not perceptibly heated. Hence IOO is automatically connected acrossthe fieldterminals; By varying the resistance of this shunt the fieldsare more or less highly excited and the current thus controlled. Thisshunt is connected between D and D and by connecting D and D and D and Dthe same shunt can be used going in either direction. In this case thesegments are so designed that in one position of the armthe fingers makecontact on both D and B on one side and D and B on the other side and inthe other po sition contact is made on B and D and B andDThisiseasilyaccomplishedbychamfering the adjoining edges of the segmentsin such a way that the fingers drop into the groove thus formed. Thus itis seen that the energy due to the momentum of the armature and the loadto which it is attached form, primarily, the braking force. Hence nouseful power is expended in making the stop. The braking force isapplied directly to the armature, where it has the greatest advantage,and is applied without the intervention of solenoids, brake-bands, orfriction devices.

The device forapplying the brake can be ap' plied directly to thecontroller or starting-box by means of which the motor is operated. Themotor is thus under the complete control of one lever. No additionalwires are necessary between the motor and the controller.

In the case of a reversing-motor the segments and contact-fingers arearranged in such a way that the armature is brought to a stop before thecurrent can be reversed through it. Thus the possibility of plugging themotor is precluded. By plugging is meant the sudden reversal of thecurrent in the armature. The heavy rush of the current due to this andits consequent bad effect upon the armature is well known. This alone isan extremely-valuable advan tage which the device possesses. Its use asa brake in connection with the controller puts the motor under completecontrol, which, for instance, in crane-service is of great valve.

Equipped with my improvement the trolley can be run out all the way atfull speed, the

a quick positive stop owing to the air which the brake-band entrainsbetween itself and the brake wheel. lVith the controllerbrake the stopcan be made as quick and decisive as desired.

When my invention is applied to a motor running in one direction only, Idesign the controller as shown in the diagram Fig.

I claim as my invention-- 1. The combination in a motor-controller, oftwo series of concentrically-placed resistance-blocks, a contact-armhaving four sets of fingers thereon constructed to bear on said blocks,two series of brake-blocks placed similarly to the resistz'tuce-blocksin the path of the contact-arm, connected to the motorcircuit anddisconnected from the line,whereby the motor is made to act as a seriesgenerator when running under its own momentum, thus retarding the motionof the armature Without using current from the line, substantially asdescribed.

2. The combination in a 1notor-controller of two concentrically-arrangedseries of contact-pieces, a contact-arm and two sets of contact-lingersthereon, movable over the contact-pieces, said pieces consisting ofresistance points or blocks, brake-blocks and deadblocks, thedead-blocks intervening between the resistance and the brake blocks andthe brake-blocks being connected to the motorcircuit and not to theline, thereby short-circuiting the motor on itself when the said contact-arm rests on the brake-blocks, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ARTHUR G. EASTWOOD.

Witnesses:

J. A. ()BENCHAIN, H. S. CHILEs.

